Recycling of iron and titanium resources from early tailings: From fundamental work to industrial application.

The comprehensive recovery of iron and titanium resources from early tailings were systematically attempted from fundamental work to industrial application. Geochemical characterization of the tailings was first conducted, followed by the iron recovery and titanium recovery. Iron recovery was mainly achieved through a series of magnetic separation, and titanium recovery was on the combination of magnetic pre-concentration and flotation separation. Special for titanium recovery, different pretreatment methods including ultrasonic cleaning and attrition-scrubbing were studied to reduce the influence of serious surface pollution of early tailings on ilmenite floatability, and attrition-scrubbing proved to be the best one. Associated mechanisms of flocculants influence on ilmenite floatability and the attrition-scrubbing effects were explored using micro-flotation and XPS tests. After a series of fundamental studies, the industrial production of iron and ilmenite concentrate went into operation and the industrial debugging results were roughly satisfactory. At last, a brief economic analysis was given for the present work.

Reconstruction of the ossicular chain with titanium implants.

OBJECTIVES: Since 1994 more than 1300 titanium implants have been used to reconstruct the ossicular chain of the middle ear for chronic otitis media. Two different types of implants were used. First, a total and a partial implant of fixed length, available in numerous different lengths. And second, a total and partial implant that has an adjustable length. The implants are commercially available from 2 different companies. Patients were followed for a postoperative term from 6 to 72 months. METHODS: A wide variety of patients aged 5 to 82 years received a tympanoplasty type III. Those patients whose ossicular chain had been reconstructed with titanium implants since 1994 were evaluated. As implants from one company are fixed in length; implants of a second company are trimmable in length. All prostheses are lightweight and made of pure titanium, fitting most anatomical situations. RESULTS: Earlier results already showed a very low complication rate. Extrusions occurred only in cases of middle ear atalectasis with resorption of interposed cartilage (<1%). No adverse reaction to the prostheses could be seen, even in histologic reviews. An average air-bone gap less than 20 dB(A) for all calculated frequencies of 0.5, 1, 2, and 4 kHz was achieved for 76% of cases; 43% of cases showed a calculated air-bone gap of less than 10 dB(A), only 10% higher than 30 dB(A). CONCLUSION: All implants used offer the proven benefits of titanium, namely high biocompatibility and high stability at a very low complication rate with excellent hearing results for the patients. Titanium implants can highly be recommended to reconstruct the ossicular chain of the middle ear.